HOT MIX ASPHALT LONGITUDINAL JOINT DETERIORATION

Abstract

The notched wedge joint design has proven to be the preferred method of joint construction by research studies given the obvious benefits of higher density, reduced permeability and greater edge confinement when compared to traditional joint methods. Greater quality of joints and improved pavement performance is evident in states that specify the joint type, but not without careful quality control during the construction process. Pavements exhibit longitudinal joint cracking as early as three years into the service life of a roadway, exposing the pavement to damage and costly repairs, or total replacement. Workmanship determines the quality of the finished joint and good construction is the only means to reduce permeability caused by low densities. The notched wedge joint design seems to ensure higher densities and less potential for failure. Prior to this study, contractor input was rarely solicited by the Wisconsin Department of Transportation (WisDOT) or by the industry as a whole. State roadway projects were chosen based on DOT collected information, and contractor representatives were surveyed to gain a greater understanding of the contractor perspective and process. The survey results exhibited many commonalities in method as well as differences in opinions and unique practices supported by industry research. This information was analyzed and used to propose specification revisions and to develop recommendations for a joint density testing process for performance data collection.